/**
 * Copyright (c) 2012-2017, www.tinygroup.org (luo_guo@icloud.com).
 * <p>
 * Licensed under the GPL, Version 3.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * <p>
 * http://www.gnu.org/licenses/gpl.html
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.tinygroup.jspengine.el.parser;

import java.io.Serializable;

/**
 * Describes the input token stream.
 */

public class Token implements Serializable {

    /**
     * An integer that describes the kind of this token.  This numbering
     * system is determined by JavaCCParser, and a table of these numbers is
     * stored in the file ...Constants.java.
     */
    public int kind;

    /**
     * beginLine and beginColumn describe the position of the first character
     * of this token; endLine and endColumn describe the position of the
     * last character of this token.
     */
    public int beginLine, beginColumn, endLine, endColumn;

    /**
     * The string image of the token.
     */
    public String image;

    /**
     * A reference to the next regular (non-special) token from the input
     * stream.  If this is the last token from the input stream, or if the
     * token manager has not read tokens beyond this one, this field is
     * set to null.  This is true only if this token is also a regular
     * token.  Otherwise, see below for a description of the contents of
     * this field.
     */
    public Token next;

    /**
     * This field is used to access special tokens that occur prior to this
     * token, but after the immediately preceding regular (non-special) token.
     * If there are no such special tokens, this field is set to null.
     * When there are more than one such special token, this field refers
     * to the last of these special tokens, which in turn refers to the next
     * previous special token through its specialToken field, and so on
     * until the first special token (whose specialToken field is null).
     * The next fields of special tokens refer to other special tokens that
     * immediately follow it (without an intervening regular token).  If there
     * is no such token, this field is null.
     */
    public Token specialToken;

    /**
     * Returns a new Token object, by default. However, if you want, you
     * can create and return subclass objects based on the value of ofKind.
     * Simply add the cases to the switch for all those special cases.
     * For example, if you have a subclass of Token called IDToken that
     * you want to create if ofKind is ID, simlpy add something like :
     * <p>
     * case MyParserConstants.ID : return new IDToken();
     * <p>
     * to the following switch statement. Then you can cast matchedToken
     * variable to the appropriate type and use it in your lexical actions.
     */
    public static final Token newToken(int ofKind) {
        switch (ofKind) {
            default:
                return new Token();
        }
    }

    /**
     * Returns the image.
     */
    public String toString() {
        return image;
    }

}
